Decarbonization: Tackling the Climate Crisis

RADU CUSTELCEAN: It took a while to realize the significance. It wasn't one Eureka moment.

DAVID SHOLL: People really want to do things differently, and develop new technologies and use them in wise ways.

ANCA TIMOFTE: I think if we believe in the goals and invest in solving climate change, then this can be done.

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JENNY: Hello everyone and welcome to "The Sound of Science," the podcast highlighting the voices behind the breakthroughs at Oak Ridge National Laboratory.

MORGAN/JENNY: We're your hosts, Morgan McCorkle and Jenny Woodbery.

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JENNY: As our planet heats up, we're facing more frequent extreme weather events, rising ocean temperatures, and deteriorating air quality.

MORGAN: Each year brings new record-breaking climate events and alarming trends that show no signs of slowing.

JENNY: Climate change is a multi-faceted problem, but we know that carbon dioxide emissions from human activities play a big role in fueling these grim milestones.

MORGAN: And while it's easy to think of industry being the main source of these emissions, the truth is, we all contribute daily. Whether it's by driving to work, heating our homes, or even the food we eat, it all adds up.

JENNY: With our modern society being so carbon-dependent, it's hard not to look at this issue and feel overwhelmed.

MORGAN: But as daunting as it may seem, scientists are not shying away from finding ways to combat this crisis.

JENNY: At Oak Ridge National Laboratory, researchers are pioneering innovative solutions to address climate change head-on. This research includes designing innovative materials to store energy, advancing new forms of carbon-free power, like fusion energy, and developing technologies to capture carbon out of the air.

MORGAN: All this research supports the grand goal of decarbonization - cutting back on the amount of carbon we put into the atmosphere.

JENNY: In this episode, we'll learn about some promising research underway at ORNL that tackles this enormous challenge.

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MORGAN: At its core, decarbonization is the process of reducing carbon dioxide emissions across all sectors of the economy.

DAVID SHOLL: Carbon emissions come from essentially every action in modern society. And in the U.S., CO2 emissions are roughly evenly split between transportation, so cars, planes, buses, everything, industry, so manufacturing of everything that we use in our daily lives, and then buildings, both commercial and home residences. So that's roughly a third, a third, a third. And then there's a smaller contribution that comes from agriculture, and interestingly a lot of the agricultural contributions are not necessarily from CO2. There are other greenhouse gases that are emitted.

JENNY: That's David Sholl. He's the executive director and vice provost of the University of Tennessee-Oak Ridge Innovation Institute.

MORGAN: It's easy to understand how heating and cooling our homes and putting gas in our cars contribute carbon emissions, but the release from industry may be less obvious to the average consumer.

SHOLL: Most of us in our daily lives don't see anything get manufactured. We don't see plastic being manufactured. We don't see food being processed. It just shows up in our life somehow. Those are the ones that are actually quite difficult for most of us to understand, because they're sort of invisible to us. But again, it's a third of all the emissions in the country. It's a big amount.

JENNY: While decarbonization is not exactly a household name, you've probably heard the term net zero.

SHOLL: There are some subsets of decarbonization and the one that many people will have heard of is net zero. That's a goal for a society or a company or a group, by some target date to reduce their emissions to zero. That's a very challenging goal, and so decarbonization refers to any step along that pathway. I think of decarbonization as a descriptive term. It describes the goal of where we're going. We want to take the carbon emissions out of our economy and carbon emissions come from every single part of the economy. So, it's really hard to do.

MORGAN: Of course, climate change isn't something the U.S. is experiencing alone. It's a global problem.

JENNY: In 2021, the U.S. Department of Energy formed the Net Zero World Initiative, which is a partnership of nations around the world working together to meet their climate goals and move faster towards clean energy solutions. ORNL and other DOE national labs are supporting the effort.

SHOLL: The foundational reason we need to engage globally is this is a global problem, right, and no one country can address the problem by itself. It makes it a really challenging issue because, of course, different countries have different agendas and there are legitimate concerns that if you change your economy that maybe you give other people a competitive advantage. I think one thing that's been recognized in the past few years in the U.S. and other places as well is there will be huge growth in the clean tech field. And so, there's a huge economic incentive to be a leader in doing that. And so it makes sense that for us in the U.S. that we want to lead those things.

MORGAN: To help the U.S. meet its carbon reduction targets, scientists at ORNL are working on a range of decarbonization technologies.

JENNY: The lab established its Transformational Decarbonization Initiative in 2021, which is led by David, to put greater emphasis on research in this area.

SHOLL: The Transformational Decarbonization initiative, TDI, is a specific subset of work at ORNL on decarbonization, and it's particularly focused on net negative technologies. So, we've talked about things that we do today that emit greenhouse gases. Some of those will be really hard to change. And so many people believe that we'll need technologies that can actually take CO2 out of the environment in a concentrated way. And so those are the things we're working on in TDI. We have a portfolio of projects. Some are very technology focused, engineering focused. We're looking at removing CO2 from ambient air, for instance, and that's sort of an engineering approach. But we also have things we're looking at that are more natural world approaches, so understanding how soils can take up carbon.

MORGAN: This focus on net negative technologies complements other work going on across the lab.

SHOLL: If you look across ORNL, we have a huge portfolio of work - in all of the today's sectors of the economy. So, we have a huge group of people working on transportation. How do we modernize transportation? We have a huge group of people working on industrial processes. The idea of TDI is to complement those. Not to say that net negative is more important than those things, but we're going to need all of those things together. The other advantage, I think, of working on the net negative technologies is these are technologies that don't exist today, and so there's a prime role for the kind of R&D that a national lab can do.

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MORGAN: In 2016, tackling climate change wasn't exactly on the mind of ORNL chemist Radu Custelcean.

JENNY: He and his team were hard at work looking for ways to remove environmental contaminants such as sulfate, chromate or phosphate from water.

MORGAN: But as luck would have it, their experiments inadvertently revealed a novel method for capturing carbon directly from the air.

RADU CUSTELCEAN: It was indeed a serendipitous discovery. We are doing basic research on ion recognition and separation. And as part of this research, we came up with a new class of receptors, called bis-imino-guanidine, or BIGs. One day we tried to crystallize one of these BIG receptors, and in doing so, we had a surprise that it, as it crystallized in the presence of air, it grabbed carbon dioxide out of the air and crystallized together. So that was quite it was surprising at that time, and but it changed the course of our project.

JENNY: This accidental discovery set off a chain of events that led to significant insights into carbon capture. Initially, the team didn't fully grasp the importance of what they'd found.

CUSTELCEAN: It took a while to realize the significance. Right away, we realized, basically, when we solved the crystal structure. So, this was over a course of a week. It wasn't one Eureka moment. These molecules, usually you try to crystallize something, it takes days or even weeks.

JENNY: The team faced a series of challenges in understanding the full implications of their discovery. They determined that the crystals had captured carbon dioxide from the air, but the process was complex and required further research to be viable.

CUSTELCEAN: We put it on the x-ray diffractometer and we collected data to determine its crystal structure. And the next day we processed the data and the data wouldn't fit to just the ligand. And it was clear that it was something else. And then once we realized it's carbonate, then it didn't take us too long to realize that the only source of carbonate anions was the carbon dioxide from the air. Once we realized that, then we realized this is a process of separating carbon dioxide from the air.

MORGAN: Recognizing that they had a method to capture carbon dioxide from the air was only the first step. The next challenge was figuring out how to release the captured CO2 efficiently and sustainably.

CUSTELCEAN: You have to close the cycle and the harder part, we realized, was to actually release the carbon dioxide and then collect it to send it for storage but then recycle these ligands, these BIG ligands. And how much energy is involved? That was also a big question, because if it takes a lot of energy then it's not sustainable.

JENNY: Over the course of a few years, Radu's breakthrough led to the development of a patented technology that caught the attention of entrepreneur Anca Timofte.

ANCA TIMOFTE: I had been in the direct air capture space and carbon removal for about eight years at the time, and was in business school at Stanford. I was keeping an eye out on all the new research that was coming out of universities, national labs, and just in general the scientific discourse around direct air capture and carbon removal. I came across the work published at Oak Ridge by Radu Custelcean on his novel chemistry for direct air capture. And that really appealed to me. It was completely different than what I had seen before. And we're both of Romanian background. So, we had that small connection that I think like maybe was an extra reason why I paid even more close attention to his work. I had reached out and talked to him about his work and got more and more interested. The more I learned about the chemistry and saw its potential, especially again at that time, there were a couple of other solutions out there, but this was completely different and novel in the sense that it held promise.

MORGAN: Anca is the co-founder of Holocene, a startup company focused on designing and building plants that remove carbon dioxide from atmospheric air. She licensed Radu's technology from the lab in 2023.

JENNY: Now she's developing her business through Innovation Crossroads. This program, funded by the Department of Energy and the Tennessee Valley Authority, supports entrepreneurs in bringing their innovations to market.

TIMOFTE: What Innovation Crossroads allows for is a simpler way for an early-stage founder or entrepreneur to work with the national laboratory. They offer mentorship, funding to work with the lab, programming specific for entrepreneurship, and access to not only the scientists who I had met through these conversations, but also just like the national lab as a whole.

MORGAN: Innovation Crossroads provides Holocene with a two-year cooperative research and development agreement, allowing continued collaboration with Radu and ORNL.

TIMOFTE: I wanted to really understand what I'm licensing and also what are the advantages and challenges of the chemistry. What was really helpful originally is having access to the people who knew most about this, which were the inventors of the chemistry. I think that made the licensing process easier and the technology transfer process that comes with the license. So very grateful for that support and collaboration.

MORGAN: With the fundamental chemistry from Oak Ridge in place, Holocene has been building on this platform and scaling up the technology for commercial use. In May, the company opened its pilot plant in Knoxville, Tennessee - and Anca and her team are already planning for the company's next milestone.

TIMOFTE: The step that we've just accomplished is essentially like leaving the laboratory, leaving bench scale behind and operating now with atmospheric air. In real conditions, in real weather. We're at 10 tons of carbon dioxide per year capacity. And we're already started engineering the next size plant, which is 200 to 500 times bigger. Obviously, that doesn't mean the next hundred thousand times is as easy. It will take us a little time. It will be more complicated, but we're trying to move quickly.

JENNY: Even as the company scales up, Anca recognizes the sea change that will have to occur for Holocene - and other net-negative companies - to make a significant impact on climate change.

TIMOFTE: This whole industry will have to grow to be pretty much oil and gas in reverse. It is an incredible - I don't want to minimize the numbers - it is an incredible transformation of many different sectors of the economy, right? It's about doing oil and gas in reverse in terms of volumes or mass that we would have to move from the atmosphere back into the ground. So, supply chains, energy, all of the workforce needed. There's a lot of things. I think we understand the size of the challenge, and it's just a matter of getting good technology in place, getting a lot of government support, and all of these pieces. I just want to put that into context. It's been done before. If we believe in the goals and invest in solving climate change, then this can be done.

MORGAN: We asked Radu what it's been like to see his research go from a few crystals in a laboratory to a commercialized technology that could one day have a global impact.

CUSTELCEAN: So, it's a long process. It's a long transition from basic research to applied research. Sometimes it can take decades. In this case, I was surprised it actually took just eight years. From the initial lucky discovery to today when a company actually tries to commercialize, scale up and commercialize this technology. So that's very short in this business. And it's very rewarding to be honest. It took a while for me to get to the point to actually find something from the basic research that led to an application, because a lot of basic research is very esoteric, and it's useful, but it doesn't have immediate application. So, it has to happen at the right time, and in this case it did.

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MORGAN: In addition to novel technologies, scientists are also researching how to integrate carbon capture methods into existing infrastructure.

JENNY: As you heard earlier, buildings make up about a third of carbon emissions in the U.S. With about six million of those being commercial structures, ORNL's Kashif Nawaz see as an opportunity to deploy cost-effective carbon capture technology on a wide scale.

MORGAN: Kashif and his team have developed an innovative filter that can be retrofitted to the air handling units of existing commercial buildings - turning them from carbon sources to carbon sinks.

KASHIF NAWAZ: In the building air handling units, we move a lot of air to condition it, to heat up, cool down, remove moisture, in some cases add moisture. So, what we are doing here is just adding one more capability, if you will, by integrating the direct air capture module to those rooftop units. So, it's effectively right now more or less a filter approach where we have, you can think about, a stack of 90 modules which are placed together.

JENNY: This stack of modules allows the team to gather important scientific data on how variables like flow rate, temperature and humidity impact the performance of the carbon capture material.

NAWAZ: We have completed the capture part effectively, where we have demonstrated that a rooftop unit can be retrofitted to remove a good amount of CO2 from the air. To give you some context, an average 12.5-ton cooling and heating capacity rooftop unit, the one we're using here at the lab, which we are working on, it can remove about eight to 10 tons of CO2 per year.

JENNY: In addition to developing effective carbon capture technology, Kashif and his team are also focused on making the filter material itself more sustainable.

NAWAZ: The material after a certain period of time can get saturated. Some of the materials get saturated fairly quickly, some classes of materials take much longer. There are different approaches. If a material has more quick transient behavior, that means it has a tendency to get saturated within minutes or hours. There are ways where we can effectively deploy them in a wheel configuration. This is very well established in buildings for moisture removal, we call them enthalpy wheels. The way they operate is on one side, you are removing it while on the other side you are continuously regenerating it, so we can effectively have a continuous separation process.

JENNY: The goal is to implement a similar continuous regeneration process for the carbon capture filters, making them more sustainable and efficient.

NAWAZ: If a material takes, say, a week long to get saturated, there are ways where effectively those filters can be removed and taken offsite for regeneration. But in this case we are going to add another regeneration mechanism which can actuate the regeneration process onsite so that we don't have to physically remove the materials, and we can have more of a sustainable operation.

MORGAN: Even as the team makes improvements to this approach, the goal is to make deployment of these solutions as easy as possible.

NAWAZ: There are more sophisticated solutions which can provide better performance, much better performance and process control, such as the rotating wheel concept. So, in that case, again, it will be a part of the same package, the boxes, which is on the top of the buildings for air conditioning. So, it's not going to add any significant footprints, if you will. And the deployment can be fairly simple, just attaching that filter towards the condenser coil, or it can be more involved where we have to really redesign the whole package unit to integrate it within that system.

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JENNY: We've only scratched the surface when it comes to decarbonization research happening at ORNL.

MORGAN: We asked David Sholl to reflect on the challenges - and opportunities - of conducting research in net negative technologies that could take years or even decades to make an impact.

SHOLL: The net negative things, they're not commercial products today, typically, but the goal is that let's say by the mid 2030s, these are really large-scale technologies that are capturing hundreds of millions of tons of CO2 per year.

And that's a very, very challenging timeline. But it does mean that there's a period now where we need to do that foundational R&D, but with an eye towards how we scale it. We have to be thinking about how do we get this out, who are our future partners, how will they do it at larger scale?

JENNY: Despite the obstacles, David sees plenty of cause for optimism.

SHOLL: Do I feel hope most days? I do, yes. This is going to be a really long journey. I think it's really important not to worry about small changes in government policy from day to day because this is a decadal journey. We really have to change things that will look different today in 2024 and 2034 and 2044.

And by necessity there will be many bumps in the road along the way. But yeah, I do have a lot of hope. I see especially a lot of the industrial partners that we work with are really deeply committed to changing their technologies. So, people really want to do things differently, and develop new technologies and use them in wise ways. So, it's going to be an exciting journey ahead, I think.

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JENNY: Thank you for listening to this episode of the Sound of Science.

MORGAN: We hope you enjoyed it and will subscribe wherever you get your podcasts.

JENNY: If you're interested in ORNL's decarbonization research, follow us on social media for the latest.

MORGAN: Until next time!